Remaining forests on the Central Highlands of Madagascar—Endemic and endangered aquatic beetle fauna uncovered

Abstract Madagascar is known for its high endemism and as many as 90% of this unique diversity are forest‐dwellers. Unfortunately, the forest cover of Madagascar is decreasing at an alarming rate. This decrease can also affect aquatic insects, but our knowledge on aquatic insect diversity and distribution on Madagascar are limited. Although the eastern rainforests are considered the most diverse, the Central Highlands of Madagascar also harbors unique microendemic fauna but has been less studied. Here, we analyze the aquatic Adephaga beetle fauna of three remaining protected forests of the Central Highlands. Diversity, abundance, and uniqueness are compared between and within natural forests and surrounding grasslands. At least 15 undescribed species were found, highlighting the Central Highlands as an important area for endemism. The natural forests and the surrounding grasslands differed significantly in species assemblages. Interestingly, the three remaining forests differed in their assemblages with the geographically more distant Manjakatompo Ankaratra having the most unique fauna but also the highest altitude span. By contrast, the species composition was similar between the peripheral zones of each of the three remaining forests. The similarity of the fauna in the peripheral open habitats illustrates how some local forest endemics are replaced with widespread generalists in degraded habitats. Our study shows that the remaining forests of the Central Highlands of Madagascar are important refuges of unique fauna at high risk of extinction.


| INTRODUC TI ON
Madagascar harbors exceptional levels of endemism and is classified as a biodiversity hotspot (Myers et al., 2000). The long geological history of isolation in combination with a great variety of topography, geology, and climate are the main factors behind this richness Ganzhorn et al., 2014;Vences et al., 2009). As much as 90% of Madagascar's endemic diversity is associated with forests (Allnutt et al., 2008;Dufils, 2003;Goodman & Benstead, 2005). The majority of these species are found in native undisturbed forests, although a subset can survive in disturbed forests, secondary vegetation, and grasslands (see Irwin et al., 2010 for a review). The high level of deforestation in Madagascar, historically and currently, is therefore of greatest concern for conservation (Allnutt et al., 2008;Green & Sussman, 1990;Vieilledent et al., 2018a). A recent study found that Madagascar has lost 44% of its forest cover between 1953 and 2014 and that the deforestation rate was increasing alarmingly in the later years measured (99,000 ha/year in 2011-2014; Vieilledent et al., 2018a). For the period 2015-2017, this trend had accelerated further, reaching levels of 162,000 ha/year with roughly half of Madagascar's remaining and fragmented forests now being less than 100 m from a forest edge (Vieilledent et al., 2018b). With the average deforestation rate in the period 2010-2019, undisturbed humid forests in Madagascar are predicted to have completely disappeared in less than 30 years (Vancutsem et al., 2021).
Beta-diversity, or species turnover, is generally very high in Madagascar, as most endemics are restricted to specific geographical regions on the island. Conservationist's concern with forest fragmentation is therefore not only a matter of fragment size, numbers, and interpatch distance but also of geographical location. The eastern rainforest biome is generally regarded as the most diverse and many of Madagascar's protected areas are distributed along the eastern escarpments. One interesting geographic area that has received little attention, is the Central Highlands of Madagascar. Even if the remaining forests here are very small, these remnants harbor significant highland-endemic diversity ( Figure 1; Andreone et al., 2007;Hjalmarsson et al., 2013;Raxworthy & Nussbaum, 1996).
The Central Highlands is today largely open secondary grasslands with few remaining forest fragments. The largest remaining forests are Manjakatompo Ankaratra, Ambohitantely, and Anjozorobe-Angavo (Goodman et al., 1996). It is debated whether all of the Central Highlands was entirely forested before humans arrived, or if open grasslands may have existed prior to human colonization (Bond et al., 2008;Godfrey & Crowley, 2016;McConnell & Kull, 2014;Vorontsova et al., 2016). High endemism levels, lineage origination since Miocene, and regionalization of grasses (Bond et al., 2008;Hackel et al., 2018;Vorontsova et al., 2016) as well as evidence of pre-human retraction of forests (Quéméré et al., 2012), suggest that some areas were naturally at least partly open land before humans arrived. The Central Highlands might thus have been a mosaic of forests, woodland, and more open savannah. However, the great expansion of grasslands at the expense of forest cover is indisputable in recent historical times (Crowley & Samonds, 2013;Godfrey et al., 2019). Multiple lines of evidence show a rapid biotic change around one to one and a half millennia ago (Burns et al., 2016; human presence on the islands is confirmed for a minimum of 2000 years: Douglass et al., 2019). Charcoal becomes much more prominent in layers from this time (Burney et al., 2003), C4 grasses expanded at the expense of C3 woody plants (Burns et al., 2016), and the megafauna collapsed Goodman & Jungers, 2014).
There were two main aims with our study. The first was to compare the aquatic Adephaga beetle fauna of three forest vestiges of F I G U R E 1 One of the many undescribed species and local endemics of the Central Highlands of Madagascar. This is a new diving beetle species of the genus Uvarus (Dytiscidae) from Manjakatompo Ankaratra. Length 2.6 mm.
the Central Highlands. Such a comparison will provide information on how these areas overlap in species assemblages and which area that has the most unique invertebrate fauna. The second aim was to compare the species assemblages of the forest fragments with the surrounding savannah/grassland in the nonprotected zone outside each protected forest area. This information allows us to compare the difference in species assemblages between forests vs savannah/ grassland and to examine to what degree forest-dwelling endemic species survive in deforested habitats.

| Study area
The Central Highlands covers a large part of the island and takes on the west of the North-South running eastern escarpment and declines gently towards the west (Andrianarimisa et al., 2000;Goodman et al., 1996). The Highlands region represent over 40% of Madagascar with an elevation above 800 m. The study was conducted in the three separate remaining forests Manjakatompo Ankaratra, Ambohitantely, and Anjozorobe-Angavo, all situated in the central portions of the Highlands (Figure 2). Brief descriptions of these areas are provided below, while Goodman et al. (2018) provide more detailed descriptions.

| Manjakatompo Ankaratra
The forest part of Manjakatompo Ankaratra (official name: Réserve de Ressources Naturelles de Manjakatompo Ankaratra) is located on the eastern slopes of the Ankaratra Massif. The reserve covers an area of 8130 ha and has a very high range in altitude starting from about 1500 m to 2643 m. The forest has been under severe anthropogenic pressures lately, heavy deforestation for charcoal production and regular fires Hjalmarsson et al., 2013;Rabemananjara et al., 2012;Ranarilalatiana et al., 2019).
The moist and evergreen forested parts are mostly between 1600 and 2000 m, and above 2000 m extensive grasslands extend with some pockets of ericoid thicket and bushes, heathland, and montane wetlands Guillaumet et al., 2008;Vences et al., 2002). The climate is moist and cool with cold and dry austral winter, and warm and wet austral summer (Vences et al., 2002). The average annual rainfall is 1424 mm , which falls mainly between November and April .

| Ambohitantely
Ambohitantely (official name: Réserve Spéciale d'Ambohitantely) is located on the Central Highland of Madagascar on a distinct geological formation known as the Tampoketsa d'Ankazobe plateau. It has been legally protected since 1951. The reserve covers 4950 ha (5600 ha based on the decree in force) and consists of 80 forest fragments , the largest currently 1160 ha Langrand, 1995Langrand, , 2003. Apart from the natural forest fragments, some 35% of the reserve area is made up of grasslands and approximately 15% of exotic tree plantations, mainly Eucalyptus and Pinus (Bastian, 1964;Langrand, 1995). The forest fragments of Ambohitantely are among the last natural forest habitats in the central portions of the Central Highlands .
The largest forest fragment lies between 1550 and 1660 m in altitude (Langrand, 1995(Langrand, , 2003, while more than half of the reserve area is in the 1251-1500 m altitudinal zone . The forests of Ambohitantely are classified as medium altitude moist evergreen forest with flora showing clear affinities to the eastern escarpment . The climate is cool and subhumid with an average rainfall of 1461 mm (1981) that mainly falls between November and April.

| Anjozorobe-Angavo
The Anjozorobe-Angavo forest corridor (official name: Paysage Harmonieux Protégé du Complexe Anjozorobe-Angavo) stretches north-south along the rim between eastern and western drainages about 45 (S end) to 70 (N end) km northeast of Antananarivo. As a larger (until recently) relatively intact forest, it has been used as a control or reference site to fragments of Ambohitantely in several vertebrate studies on the effects of forest fragmentation and habitat patch size (Goodman & Rakotondravony, 2000;Langrand & Wilmé, 1997;Vallan, 2000). The protected area covers 41,100 ha with more than half of the area in the altitude zone between 1251 and 1500 m . The natural forest vegetation, currently comprising 28,000 ha (Vololonirainy & Mietton, 2013), is classified as a medium altitude moist evergreen forest

| Fieldwork and sampling
We sampled water beetles of four families: Dytiscidae (diving beetles), Gyrinidae (whirligig beetles), Noteridae (burrowing water beetles), and Haliplidae (crawling water beetles). All belong to the Adephaga suborder of beetles. The habitats were classified as lotic (running water), lentic (standing water) or hygropetric (a thin water film on wet rocks by, e.g., seepages and cascades). Localities inside protected area boundaries largely correspond to forested habitats and outside protected areas to deforested habitats except for Manjakatompo Ankaratra where several localities within the protected area emphasized its advanced state of degradation, and in the alpine zone of the protected area above 2000 m, there is no forest cover. For the larger Anjozorobe-Angavo, the sampling was restricted to the northwestern part of the protected area. We sampled a minimum of five localities inside and five outside the protected area boundaries and focus on lotic environments, but a few localities were lentic and one hygropetric (the latter excluded from statistical analyses, see below).
The collecting method consisted of a semi-quantitative sampling approach. For each locality, the sampling time was around 2 h, and all aquatic Adephaga specimens recovered in the net were sampled to give an abundance measure per species. The specific sampling positions at each locality were chosen to cover the different types of microhabitats. Sampling was done using a hand water net (0.5 mm mesh size) and sieves with different sizes, depending on the water body size and the type of microhabitat. Specimens were preserved in labeled plastic tubes containing 95% ethanol. The samples were stored in a laboratory refrigerator for subsequent sorting and identification.

| Sample preparation and identification
All samples were sorted and identified to species level using identifi- genitalia were extracted with fine forceps or a pin from the tip of the abdomen and glued onto a card together with the dry-mounted specimen for examination under a microscope (Leica MZ12.5). Specimens are stored at the Swedish Museum of Natural History, Stockholm. The samples included several undescribed species, and these have been numbered as morphospecies 1, 2, 3, sometimes with a "working name" for reference within quotation marks. None of the names herein used are issued for the public and permanent scientific records or for purposes of zoological nomenclature (ICZN article 8.2). This also applies to the "working names" of undescribed species that will be formally described elsewhere. A few species belong to species complexes yet to be resolved and here the informal term cf. is used. It is here to be understood as indicating affinity to the named species following cf. but may or may not be conspecific.

| Statistical analysis
Differences in species richness among areas (the three reserves) and location (inside the protected forest and outside in the peripheral zones) were investigated using rarefaction curves with the iNEXT package (Chao et al., 2014;Hsieh et al., 2016Hsieh et al., , 2022 in R statistical software (ver 4.2.1 R Core Team, 2022). Curves were fitted using sampling-units incidence matrices that indicate the presence/ absence of species. These curves were extrapolated to the total number of samples in an area for inside/outside curves, and to 20 localities for area curves to better show the general trajectories. We used 50 bootstrap replications (the default) to create confidence intervals around the curves.
To compare species assemblages between the forest reserves and between forest reserves and peripheral zones we performed multivariate (multi-species) analyses. First, we fitted generalized linear models (GLMs) with a negative binomial distribution using the package mvbund (Wang et al., 2012(Wang et al., , 2022. Community differences among areas, location, and their interaction were tested with a loglikelihood ratio test assuming the independence of species response variables (Wang et al., 2012). We performed "species-by-species" univariate tests to further explore individual species responses.
To complement the GLM approach, we also performed a distancebased test, namely a PERMANOVA based on Bray-Curtis dissimilarities (distance matrix) using the package vegan (Oksanen et al., 2019).
The same dissimilarity distance matrix was used to test for differences in beta-diversity (Anderson et al., 2006). To visualize the separation of species community across areas and locations, we used a nonmetric multidimensional scaling (NMDS), with a Wisconsin double standardization that is a gradient analysis based on a distance matrix.

| RE SULTS
3463 individuals of aquatic Adephaga were sampled across 44 localities representing 92 species, of which 74 belong to the family Dytiscidae, 12 to Gyrinidae, 5 to Noteridae, and 1 to Haliplidae (Table 1). In total 28 species were recorded at only one locality.
The total number of species, as well as rarefied species richness, was very similar between the three areas (46, 47, and 48 species; Figure 4a, Tables A6-A8). For Manjakatompo Ankaratra, the sampled species richness and rarefied species richness were higher inside than outside the protected area boundaries (42:12; Figure 4b, Table A6), but for Ambohitantely, the pattern was the opposite (18:39; Figure 4b, Table A7). For Anjozorobe-Angavo, species richness was higher inside than outside the protected area (32:21; Table A8) but rarefied species richness was equal ( Figure 4b).
Rarefaction based on individuals showed similar results (results not shown). Overall, 41 species (45% of all species) were only found inside the reserves, and 18 (20% of all species) were only found outside the reserves.
All three remaining forests housed a remarkable number of undescribed species. A few species, such as Copelatus ankaratra from Manjakatompo Ankaratra and Bidessus anjozorobe from Anjozorobe-Angavo were described recently (Bergsten et al., 2020;Ranarilalatiana et al., 2019). Others are in the process of being described and named. New species in the radiations of Africophilus, Hovahydrus, Pachynectes, Uvarus, and Madaglymbus will be described in larger ongoing revisions of these genera. Methles cf. cribratellus and Pseuduvarus cf. vitticollis are complexes with multiple species yet to be disentangled. All three areas had a very high proportion of unique species (i.e., found only within one of the three areas) with Manjakatompo Ankaratra having the highest at 42%, followed by Ambohitantely (40%) and Anjozorobe-Angavo (38%).

| Species assemblages
The single sample from a hygropetric site (collecting event MAD16-18) was very different and had only four species, of which two were unique for this dataset. This sample was removed from the species assemblages analyses, but the exclusion did not affect the overall results qualitatively. Standing water was sampled in all areas, but had low replicate numbers inside and outside all protected areas.
Hence, we did not examine whether the protected area effect is different between running and standing water.
Multivariate analysis using negative binomial models showed that the effect of location (inside vs outside protected area) was different in each area (reserve) ( Table 2). The main effect of area and location were overall larger than the interaction effect, supporting the observation that water beetle communities were mainly different among areas, and between inside and outside the reserves independently of area. Similar results were obtained by the PERMANOVA analysis (Table A1). Our NMDS ordination (stress = 0.15) illustrated the separation of the sampled habitats along the two axes ( Figure 5). Inside and outside reserve assemblages of beetles differed, but did not dominate any of the axes.
Two areas, Ambohitantely and Anjozorobe-Angavo, showed similar patterns with the distinct grouping of inside and outside the TA B L E 1 Species and number of individuals of aquatic Adephaga (Dytiscidae, Gyrinidae, Haliplidae, Noteridae) collected in the three investigated areas.  Examination of individual species responses detected eight species with an interaction effect (p < .05, Figure A2, Table A2). Of those eight species, three species were found in all areas (Rhantus latus, Laccophilus complicatus, and Copelatus distinguendus). In total, 15 species were found in all areas and the abundance of these species was often lower inside the protected areas than outside in the peripheral savannah zone, while no differences or higher abundances inside the reserve was observed at Manjakatompo Ankaratra ( Figure 6). Excluding the samples from standing water did not have a major impact on the results but the p-value for the interaction effect increased slightly for some species, for example, Laccophilus complicatus changed from 0.04 to 0.08.

Manjakatompo Ankaratra Ambohitantely
Anjozorobe-Angavo Inds. Note: Asterix (*) signifies that the current circumscription of a taxon may be erroneous with an effect on the endemic status.

| DISCUSS ION
The results of our survey of aquatic beetles show that the Central Highlands of Madagascar is an area of high endemism on Madagascar.
We found a surprisingly large number of undescribed highland endemics from the three remaining forests, at least 15, but an exact number is not possible to establish yet as some "cf." and "sp." species require more work. We found that the reserves differed among each other in species assemblages. Thus, from a conservation perspective, any one forest fragment on the Central Highland is not exchangeable or equivalent to any other. We also found that the forest reserves differed in their species assemblages compared with the areas just outside the reserves. However, the community dispersion, which is a measure of beta-diversity, did not differ between the reserves and areas outside the reserves. In addition, species richness shows no consistent pattern between inside and outside reserves. For Ambohitantely richness was higher outside and for Manjakatompo Ankaratra, it was higher inside protected area boundaries. Such absence of a strong pattern in beta-diversity and species richness between inside and outside natural forest areas has been found in other insect studies as well (e.g., Navarrete & Halffter, 2008;Niemelä et al., 2007). It can be explained by the fact that dark and cool adapted natural forest species are replaced by warm and open area adapted generalist species (Niemelä et al., 2007; see also below). Nevertheless, other studies have found higher insect diversity inside compared with outside F I G U R E 5 NMDS of beetle species composition in three areas, sampled inside and outside nature reserves. The NMDS analysis shows that outside reserve communities were more similar (located in the center of the NMDS) compared with the inside reserve communities (located on either side of the first axis). Most samples were taken in running waters. Samples from standing waters are indicated in the figure as diamonds enclosing the reserve symbols, and samples from running waters are without diamonds. Ellipses of groups show group centroid and their standard deviation. Species names are eight-letter abbreviations formed by the first four letters of the genus and four first letters of the species epithet or temporary spn/sp number as given in Table 1. Species names are added as weighted averages of their site abundances, meaning that species are located close to the sites where they had their highest abundance. Only the most abundant species is shown if species names overlap on the ordination.

F I G U R E 6
Model estimates of the inside reserve effect compared with outside the reserve on beetle abundance for species recorded in all three areas. Effects are shown for each area as there was a strong multivariate interaction effect between area and location (inside vs outside). Species with a significant Area × Location effect (p < .05) are indicated with a shaded area. For species model statistics, see Table A2. Estimates are on the log scale extracted from negative binomial models.
Despite the absence of a difference in beta-diversity and species richness in our study, forested habitat areas harbor a more unique assemblage of locally endemic species.
Overall, species assemblages from the open habitats were more similar compared with the variation observed within protected areas (outside vs inside). Assuming that these sites were once forested, this similarity can be seen as a result of two components that drive a process called biotic homogenization (Smart et al., 2006). First, local forest endemics are lost following deforestation, an observation also made for stream insects in eastern Madagascar (Benstead, Douglas, & Pringle, 2003). The endemic genus and island radia- Second, these are often replaced by widespread generalist species that either establish or increase in abundance (also see Benstead, Douglas, & Pringle, 2003;Gibon & Elouard, 1996;Irwin et al., 2010).   (Tables A6-A8). Generalists may be more tolerant to higher temperatures, siltation, and in situ primary production (Benstead, Douglas, & Pringle, 2003;Benstead & Pringle, 2004).
We did not find general differences in beta-diversity between inside and outside protected areas ( Figure A1). This result is in contrast to our expectations as we would predict a higher level of regionalization, and thereby beta-diversity in forest-dwelling  (Bukontaite et al., 2015). We only found Pachynectes outside the protected area of Ambohitantely and not in the other two sites.
Our study did not include chemical water variables like, e.g., pH and nutrients. Obviously, such variables might also affect species abundances and the richness of water beetles. Past studies have shown that the impact of water chemistry on invertebrate diversity differs between study systems, but that landscape variables and pond and stream physical variables always explain a high amount of the aquatic invertebrate diversity variation (Heino et al., 2017;Salvarrey et al., 2014;Thornhill et al., 2017). Thus, based on past studies on aquatic invertebrate diversity, that included landscape and chemical water variables as independent variables, we suggest that our results might also be influenced by chemical water variables among the sampling sites but that landscape variables probably have a major impact as shown in many other studies on aquatic invertebrates. In particular, we note that localities in the peripheral zone of Manjakatompo Ankaratra and Anjozorobe-Angavo are situated in the vicinity of agricultural areas, or their upstream river catchment conditions involve agricultural areas. This is not the case for localities in the peripheral zone of Ambohitantely, which could partly explain the relatively higher diversity outside the protected area here.  (Langrand, 1995(Langrand, , 2003. Outside the protected area the forested area was reduced by 28% between 1949 and 1992 (Hanssen, 2002). All our sites at Ambohitantely were likely forested and part of the estimated 20 × 8 km large forest block in 1897 (Langrand, 1995(Langrand, , 2003. This, together with some remaining gallery forests along streams, could explain a more species-rich fauna outside the protected area in Ambohitantely. The remaining gallery forests seem sufficient for at least short-term survival and occupancy even of forest-dwelling taxa, at the same time as open habitat taxa move in. However, the long-term survival here of Hovahydrus is uncertain as these stream-gallery forests outside protected areas are continually shrinking from yearly fires.
The vast majority of biodiversity surveys in Madagascar have focused on largely undisturbed forests in the eastern evergreen moist forest realm or the western dry deciduous forests. The Central Highlands forest pockets, surrounded by a heavily fire-altered grassland landscape, have been assumed to be locally poor in diversity (Andreone et al., 2007). A recent prominent theory to explain the microendemism pattern in Madagascar predicted higher elevations to contain proportionally lower levels of microendemism (Wilmé et al., 2006). But, especially in the herpetological literature (notably Brown et al., 2014;Raxworthy & Nussbaum, 1996), an endemic montane fauna was acknowledged, with a focus on the three highest peaks of the Highlands, Tsaratanana, Ankaratra, and Andringitra.
Treeless secondary montane heathland was rejected as recent anthropogenic habitats, albeit fire-affected, as they supported a number of montane endemic amphibians and reptiles. Our findings on water beetles add to the knowledge that the montane heath- Ankaratra. The higher elevation zone at Ankaratra with multiple vertebrate and invertebrate endemics is thus an important conservation priority for montane habitats and species Goodman et al., 1996;Hjalmarsson et al., 2013;Ranarilalatiana et al., 2019;Vences et al., 2002).
Previous studies on Vertebrates also found Ambohitantely to have a comparable species composition to Anjozorobe-Angavo. The communities were either similar (Lipotyphlan mammals ;Goodman & Rakotondravony, 2000) or had a depauperate but nested fauna compared with the larger neighboring forest (birds; Langrand & Wilmé, 1997). There are no bird species locally endemic to any of the three sites, but one mammal species (a Nesomyid rodent, Voalavo antsahabensis) is solely known from Anjozorobe-Angavo . Among amphibians, there are three species endemic to Ambohitantely (Boophis andrangoloaka, Anilany helenae, and Anodonthyla vallani), and our study adds a surprisingly large number of new species only known from here. Given the small remnant nature of the area, this is clearly a hotspot of irreplaceable midaltitude (1500-1700 m) Central Highlands fauna.
All three areas have experienced forest cover loss during the last two decades Goodman et al., 2018).
Ambohitantely has been least affected in this time window (but see Langrand, 1995Langrand, , 2003 for older exploitation), while for Anjozorobe-Angavo and Manjakatompo Ankaratra, 20%-30% disappeared . With the loss of a large percentage of the natural forest extent, it is possible that the endemic fauna of water beetles are at extinction risk since small forest reserves might have an extinction debt (Tilman et al., 1994). In addition, very little is known about the required habitat size for the long-term survival of these taxa. Therefore, conservation efforts should be directed towards the prevention of further degradation and habitat loss, as well as forest regeneration near margins (Pareliussen et al., 2006). In addition, localized endemics are at high risk of extinction from irregular events, such as the introduction of fish or if extreme drought would completely dry out normally perennial streams.
In conclusion, the loss of remaining forests of the Madagascar Central Highlands would depauperate the aquatic insect fauna on the island. The highlands are rich in local midaltitude endemics and vastly undersampled for insects. We found a remarkable number of undescribed species across a range of water beetle tribes and in all three areas. None of these were shared between any two forest fragments. In the short term, some forest-dwelling aquatic taxa can survive in gallery forest-lined water courses, but in the longer term, deforested aquatic habitats are characterized by a more similar fauna across geographical space. Ambohitantely is the last chance of retaining a >1000 ha block of 1500-1700 m midaltitude Central Highland forests with unique biodiversity. For Manjakatompo Ankaratra, the secondary forest of mixed native/ exotic trees has probably prevented the local extinction of microendemic aquatic taxa and this site also harbors unique montane fauna elements in the alpine zone >2000 m. Anjozorobe-Angavo is the largest forest block of the three forests investigated, but also the one experiencing the highest pressure and has lost 33% since 1996. Also in this forest we found local endemics, which emphasize the high priority of further biological inventories, and predict that more endemics would be revealed. This supports the view that we are still just scratching the surface of invertebrate richness in Madagascar.

CO N FLI C T O F I NTE R E S T
The authors have no relevant financial or nonfinancial interests to disclose.

DATA AVA I L A B I L I T Y S TAT E M E N T
The dataset generated and analyzed during the current study is